Dual-micing a single source: multiple tracks as one

A common technique in the studio that I use frequently is to mic the same source with more than one mic. In ardour, I will end up with two separate tracks, and I may want to tweak each track individually, and adjust the relative levels. When time comes for mixing, I want to treat both these tracks as a single track, so that I can maintain their relative level, and so I only have to make all the cuts and crossfades once without worrying about duplicating it across two tracks. Can this be done in Ardour? What is the best way?